Proceedings of International Structural Engineering and Construction, 9(1), 2022 State-of-the-art Materials and Techniques in Structural Engineering and Construction Edited by Holschemacher, K., Quapp, U., Singh, A., and Yazdani, S. Copyright © 2022 ISEC Press ISSN: 2644-108X www.doi.org/10.14455/ISEC.2022.9(1).STR-61 STR-61-1 COMPARATIVE STUDY OF MODIFIED CONSTRUCTION STAGE ANALYSIS AND CONSTRUCTION STAGE ANALYSIS FOR RC BUILDINGS NEHAL DESAI and SANDIP VASANWALA 1 Dept of Civil Engineering, Sardar Vallabhbhai National Institute of Technology, Surat, India A significant difference is found in axial shortening of vertical members in tall concrete buildings when analyzed by Construction Stage Analysis considering the effect of creep and shrinkage as compared to the conventional One Step Analysis method. In Construction Stage Analysis the self-weight of structural members, and a load of brick walls along with floor finishing load, gets added sequentially as construction is carried out. In addition to the above loads, construction loads such as the weight of formwork, the weight of wet concrete, staking of materials, and other construction loads of men and machines get imposed on the structure during construction. Also, stagewise reduction of load due to removal of formwork, material staking, and other construction loads of men and machines should also be considered during the analysis with the Construction stage method. The axial shortening of vertical members of RC buildings was analyzed by the Conventional one-step method, Construction Stage method, considering self-weight along with brick wall and floor finishing load as sequential loads. Modified Construction Stage method-in which in addition to self-weight, brick wall, and floor finishing load, above mentioned all loads that appear during construction, were added, and removed sequentially in the analysis, by taking 20,30, and 40 floor RC building models. Modified CSA gives 2.068% to 20.56% lesser axial shortening in comparison to the CSA method. The study also concludes that the difference of axial shortening between Modified CSA & CSA increases from first to a certain floor, after that it reduces till top floor. Keywords: Axial shortening, Time-dependent properties, Creep, Shrinkage, Sequential loads. 1 INTRODUCTION Researchers have done studies on the Construction stage method of analysis for RC building in which unlike the one-step method, loads like self-weight of structural members as well as loads induced due to brick walls and floor finishes were applied as per the progress of construction. Researchers recommended the Construction Stage Method of Analysis (CSA) method considering time-dependent properties of concrete like creep and shrinkage. Dinar et al. (2014) and Correia and Lobo (2017) studied the effect of self-weight on construction sequence by the computerized method. Ha et al. (2017) developed an algorithm of the construction stage and checked the results by laser survey and suggested to consider, the movement caused by the time-dependent effect of the concrete that occurs during the construction stage of a tall building in design. Samarakkody et al. (2017) developed a technique to evaluate the differential axial shortening for high-rise buildings with composite CFT columns. Afshari et al.